dillon1000/react

Visitor extension for transforming ReactiveFunction

Adds a subclass of ReactiveFunctionVisitor, ReactiveFunctionTransform, which 
makes it easier to write passes that change the shape of a ReactiveFunction. The 
two use-cases converted so far are both flattening away certain categories of 
reactive scopes — this will make it easier to add a similar pass to prune scopes 
that contain hook calls.